1. Field of the Invention
The present invention relates in general to cooling systems of water-cooled engines and more particularly to an expansion tank or coolant reserve tank connected to the top of a radiator to act as an expansion chamber as well as to provide an additional capacity.
2. Description of the Prior Art
As is well known in the art and shown in FIGS. 1 and 2, a coolant reserve tank 10 is connected through a pipe 12 to the top tank 14a of a radiator 14 so that, when the coolant in the radiator 14, cylinder block and their connections (neither shown) reaches a predetermined temperature, the coolant expands into the reserve tank 10 and, when the coolant temperature falls, it flows back into the ordinary cooling system, whereby to always fill the radiator 14 with coolant.
The coolant reserve tank 10 has a cap 10a formed with a hole or vent 10b which opens the tank 10 to the atmosphere for releasing therethrough the vapour produced in the tank 10 and making the pressure in the tank 10 equivalent to the atmospheric pressure. Various forms of such a vent are known in the art. For example, as shown in FIGS. 3 and 4, a vent 16a may be formed adjacent the top of a tank 16 or a vent 18a may be formed by a pipe 18 which passes through a cap 20.
The disadvantage of the prior art coolant reserve tank having such a vent is that during running of the vehicle, particularly on a rough road, the coolant in the reserve tank may be waved greatly and dashed or splashed into the vent to leak therethrough, possibly causing various problems such as a deteriorated cooling efficiency due to an insufficient amount of coolant, a deteriorated insulation of some electrical system which is wetted by a leaked-out coolant, and so on.